This will be the first of two posts on the use and practice of using dipwells at Fleet Pond.

Colin Gray writes:

The use of dipwells has been a recommended practice for sites where water levels vary significantly or where drainage has had (or is perceived to have had) adverse affects on the soils.

We have been gathering data since 1995 for the nine dipwells (see map below) and six water level gauges (most of the gauges came later in 1998 as there was only one prior to that year).

A dipwell is basically a length of plastic pipe with holes drilled in the side, driven as far as possible into the ground (see picture at top). At Fleet Pond the underlying gravel prevents very deep penetration, but the deepest goes down to about 1m below soil level. That is adequate as the water table is very high in the area. Each week the measurements are converted to cm above or below soil level. When our botanical surveys are conducted (each two years or so) any recorded changes can be compared to variations in water level. Thus, for example, the recorded dry years have seen an increase of bramble in the wetland areas – not a plant one would usually see in a marsh. Other plants can move in if levels remain low for longer periods. Birch and oak for example, not trees that would usually survive with their roots in water.

We have to put a cap on each dipwell to stop small mammals falling and drowning and the better dipwells also have a sealed base to stop silt rising to fill the well.

The rangers installed dipwells on Elvetham Heath Local Nature Reserve but many were vandalised and the rangers found they had not enough time to measure them regularly so the practice there died out.

Other sites do use them where water plays a significant role in the diversity of plants and particularly if it is important to maintain a certain level of soil saturation to protect a rare or endangered plant or invertebrate.

The Southern Wood Ant (Formica rufa), and pictured above and below, is a very dominant species along the eastern side of the pond, from the lower footpath right through to the DE woodlands around the car park.

Nests of the southern wood ant are usually located along woodland rides and clearings where they can intercept the spring and early summer sunshine. This isolation appears to be critical to initiating colony activity and brood development after winter. Nests will also encroach from woodland onto more open heath and scrub. Each nest may contain over 100,000 workers, several queens and, from May to July, winged gynes and males. Different nests can be interlinked by trails to form huge colonies.

The workers also form long trails to trees bearing honeydew-producing Homoptera, which they tend. They will also scavenge and take invertebrate prey. Honeydew forms a key component of their diet and the presence of suitable trees and Homoptera may be a limiting factor on populations. The southern wood ant is found across the Palaearctic from southern Europe and the Caucasus to approximately 63 degrees north.

The southern wood ant is a conspicuous ant of southern British woodlands with large aggressive workers and a prominent nest mound. As such it is relatively well recorded and studied. Populations occur locally in Wales and England as far north as Cumbria and Northumberland. It is, however, most common in southern England, particularly in south Devon, south Dorset, Hampshire, Berkshire, Surrey, Sussex and Kent. Suitable woodlands in such areas may support strong, and even increasing, populations of the species. However, there is also evidence of a contraction of its range, particularly in northern and eastern England, the Midlands and North Wales, where a number of smaller isolated populations have reportedly become extinct. In North Wales and northern England the range of the southern wood ant overlaps with that of the hairy wood ant, F. lugubris, so care should be taken in determining specimens from these areas.

In Great Britain this species is classified as Local. It is classified by the IUCN (1996) as globally Near Threatened.

Colin produced the above written material for use in Fleet Library as part of their National Insect Week exhibition this year.

Pictures taken at the volunteering event for November 2008. Quite a difference! There was a record turnout of 20 for this event, including 5 volunteers (who are or were) members of Fleet Lions. Interestingly, The Lions is the largest voluntary organisation in the world! Anyway, many thanks to all who turned up. The next such volunteer event will be on Sunday 14th December.

A few weeks ago three of us (myself and, left to right, Richard Bennett and Steve Pipe below) decided to venture out onto the pond to collect rubbish. So we donned our best wellies and life jackets, grabbed the boat from the workshop and off we went. Well I say we donned our best wellies – one of our number decided to attempt the feat wearing only trainers – which presented many muddy athletic challenges!

We dragged the boat round to the launch point and those of us with wellies pushed the boat out into the water. Those of us wearing only trainers got to sit in the boat and watch all the hard work!

The first thing we realised was how shallow the pond really is. There was only the three of us in a flat bottomed boat, but it was just about impossible to row anywhere near the edges of the pond. The problem was particularly bad around the end of Brookly stream and at Sandy Bay. In fact the picture of Sandy Bay below was taken at a point about as near as we dared try rowing in.

We managed to get right up to the edges of the reed beds though and collected plenty of rubbish – mostly the sorts of things you’d expect; empty beer cans, carrier bags, discarded tennis balls, random bits of wood etc. We did find one birthday balloon still partly inflated and, rather more worryingly, one used syringe.

The worst area for rubbish is at the end of Brookly Stream – but as I mentioned it’s impossible to access this area by boat. Unfortunately it’s also just about impossible to access it from land as well so, sadly, the rubbish in that area will have to remain there for now. In an age when the recycling and save the planet messages are so loud and clear it’s quite sad to see so much litter still discarded and damaging the environment – and especially some of the more vulnerable wildlife.

Whilst we were in the boat we took the opportunity to visit the many islands on the pond – it’s nice to see things from a different angle and it’s clear that these islands provide a wonderful haven to many birds. Talking of birds, at one stage we saw 7 herons in a cluster of treetops. Unfortunately our camera wasn’t of a high enough resolution to capture them all, but it was certainly very impressive to see.

We also checked out the newly installed Tern Islands and evidence of their use was very clear – which is excellent news.

We’ll try to get out in the boat again next year after the nesting season for another litter patrol – maybe if there are fewer of us we can get closer in to the edges – particularly at Brookly Stream. It’s not the most glamorous of jobs, though rowing around the pond was fun (and quite tiring after the first hour or so – maybe we can interest Sir Steve Redgrave in helping out next time?). We landed one big black bag of rubbish so it was a job well worth doing – but if would be so much nicer if there was no litter in the first place.

Fleet Pond Society organises and runs a series of volunteer conservation activities at the Pond. The next conservation task is this coming Sunday, November 9.

If you have never been before and fancy trying it, please just turn up (details here) or else give Colin Gray a call on 01252 616183, who will be delighted to provide additional information.

Speaking from personal experience, new volunteers are made very welcome and there is a very nice friendly atmosphere overall. Tools and advice are available – you even get tea/coffee and cakes in the mid-morning break!

Interestingly the volunteers have a very wide range of ages, backgrounds and interests. To give a flavour of this, we will occasionally provide ’spotlights’ on volunteers to explain their motivations for getting involved and what they get out of it.

Hopefully this will be an additional motivation to readers of the blog to come along and give it a go – it’s a very rewarding way of spending a Sunday morning!

Further information on volunteer events and ‘spotlight’ volunteers can be found by searching this blog.

Solitary Bees
Did you know that Britain has more than 250 species of native bee? All of these bees play an essential role by pollinating flowers. But these bees are becoming scarce, with fewer wild flowers and suitable nest sites and an increase in pesticide use. Now around 25 per cent of our native bees are listed as endangered species.

Out of these 250 species, over 90% of them are solitary bees. By solitary we mean that a single female, after she emerges from her pupae and is mated by a male, constructs, provisions and lays an egg in each cell in a nest by herself. This in comparison with social (called eusocial) bees like the Bumble Bees, Honey Bees and Stingless Bees, all of whom have a Queen who lays eggs and a number of workers who look after them.

Female solitary bees prepare their own nest in the ground, in cracks or crevices in walls, or in wood. They gather nectar and pollen as food for their own offspring, and provide little or no further care after their eggs are laid.

Leafcutter bees nest in soft, rotted wood, thick-stemmed pithy plants such as roses and in similar materials that the bees can easily cut through and excavate. Nest tunnels may extend several inches deep and coarse sawdust is thrown out at the entrance.

After the nest has been produced, leafcutter bees collect fragments of leaves to construct individual nest cells. The bees cut leaves in a very distinctive manner, making a smooth semicircular cut about 3/4-in in diameter from the edge of leaves.

These are carried back to the nest and used to fashion nest cells within the previously constructed tunnels. Each leaf-lined cell is then provisioned with a mixture of nectar and pollen. An egg is then laid and the cell sealed, producing a finished nest cell that somewhat resembles a cigar butt.

A series of closely packed cells are produced in sequence so that a finished nest tunnel may contain a dozen or more cells forming a tube 10cm to 20cm long. The young bees develop and remain within the cells, emerging the next season. Leaf-cutter bees differ from related species in that they collect pollen on their abdomens rather than on their hind legs.